The "Doomsday Clock," which represents the judgment of leading science and security experts about the perils to human existence, is to be updated on Tuesday against the backdrop of the war in Ukraine and other crises.

The Bulletin of the Atomic Scientists will announce at 10:00 am (1500 GMT) whether the time of the symbolic clock will change.

The organization describes the clock as a "metaphor for how close humanity is to self-annihilation" and says the annual resetting should be seen as a "call-to-action to reverse the hands."

A decision to reset the hands of the clock is taken each year by the Bulletin's science and security board and its board of sponsors, which includes 11 Nobel laureates.

For 2023, the Bulletin said they will take into account the Russia-Ukraine war, bio-threats, proliferation of nuclear weapons, the continued climate crisis, state-sponsored disinformation campaigns and disruptive technologies.

The hands of the clock moved to 100 seconds to midnight in January 2021 -- the closest to midnight it has been in its history -- and remained there last year.

"The clock remains the closest it has ever been to civilization-ending apocalypse because the world remains stuck in an extremely dangerous moment," the Bulletin said in a statement at last year's event.

The clock was originally set at seven minutes to midnight.

The furthest from midnight it has ever been is 17 minutes, following the end of the Cold War in 1991.

The Bulletin was founded in 1945 by Albert Einstein, J Robert Oppenheimer and other scientists who worked on the Manhattan Project which produced the first nuclear weapons.

The idea of the clock symbolizing global vulnerability to catastrophe followed in 1947.